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<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      let str = `ababababa,123ababab123,abbbbb`;

      console.log(str.match(/(ab){3,6}/g));
      console.log(str.match(/ab{3,6}/g));

      console.log(str.match(/ab+/g)); //{1,}
      console.log(str.match(/ab?/g)); //{0,1}
      console.log(str.match(/ab*/g)); //{0,}
    </script>
  </body>
</html>
